A conventional flat display device is equipped with a scan driving circuit, which is fabricating the scan driving circuit on an array substrate by a conventional thin film transistor flat display array process, in order to achieve a driving method of scanning line by line. Each scan driving circuit in the conventional flat display device merely drives one scanning line, but multiple scanning lines are disposed in the flat display device, which will need multiple scan driving circuits and complicate design of the circuit, occupying space that can be adverse to a narrow bezel design of the flat display device.